Fire-door.



No. 786,598. PATENTED APR. 4, 1905. E. OHNST-RAND.

FIRE DOOR.

APPLIOATIQN FILED SEPT. 2, 1904.

UNTTED STATES Patented April 4, 1905.

PATENT OFFICE.

ENOCH OHNSTRAND, OF J AMESTOW N, NEW YORK, ASSIGNOR TO ART METAL CONSTRUCTION COMPANY, OF JAMESTOWVN, NEW YORK, A

CORPORATION OF NEW YORK.

FlRE- -DOOR.

SPECIFICATION forming part of Letters Patent No. 786,593, dated April 4;, 1905. Application filed September 2, 1904. Serial No. 223,108.

To (Z7 whom it 'mlrty concern:

Be it known that I, Enoon OHNSTRAND, a citizen of the United States, residing at Jamestown, in the county of Chautauqua and State of New York, have invented certain new and useful Improvements in Fire-Doors, of which the following, taken in connection with the accompanying drawings, is a full, clear, and exact description.

The invention relates to the particular kind of lire-resisting shutters and doors comprising a wooden core and a covering therefor of sheet metal; and the object of the invention is to provide an eflicient means for securing the sheet metal to the core, so that the sheathing cannot come apart, even though the core were entirely destroyed.

In the drawings, Figure 1 is a side elevation of a door, showing the concealed seam or tie down the middle of the door. Fig. 2 is an edgewise view of the door, showing the seam or tie lengthwise of the same. Fig. 3 is a sectional view at line X X in Fig. 1, showing the finished seam or tie. Fig. 4 is a like sectional view with the tie in process of formation. Fig. 5 is a perspective view of the tie-strip. Fig. 6 is a sectional view showing the groove for the tie.

Similar numerals refer to corresponding parts in the several views.

The numeral 10 indicates the wooden core, which may be made solid, as shown in Fig. at, or built up in layers 11, as shown in Fig. 3, to prevent warping. A shallow groove 12 is cut around the edge of the door or down the side, according as it is desired to form a connection for the sheet metal on the side, as in Very large doors, or around the edge. A tiestrip 13 is bent from the sheet metal with flanges along each side, and holes 14 are provided at suitable distances for nails 18 for attaching to core 10. This tie-strip 13 may be attached in groove 12 before the sheeting 15 is attached to the tie-strip. The edges of the sheet metal 15 are turned inwardly, as at 16, at just the right distance from the corners 19 of the core, so that the two sides will just come together and form a closed seam 17 when the sides are pressed down in a suitable press. The nails 18 can of course be driven into the core 10 at the same time that the flanged sides are pressed into shape in the press. The enamel [lows over and entirely conceals seam 17. It is apparent that this manner of forming the blind tie clamps the flanged edges of the concealed tie-strip l3 firmly within the inwardly-bent edges of the outer sheathingand holds the same absolutely in place, so that it cannot get away. The tie-strip being also nailed to the core holds the core in place. The tie would not be affected even though the core 10 were entirely destroyed, as the tiestrip 13 firmly holds both edges of the metal covering. The concealed tie is used on the sides of large doors for doubling the sheets of metal, as shown in Fig. 1. On small doors it is of course only used around the edge of the door. Of course the tie-piece 13 would held without nailing to the core.

The core 10 is preferably built up of layers 11. The central layer is formed with alternating grooves 20 on opposite sides of the same which run lengthwise ot' the door and form spaces to receive the gases in case of extreme heat being applied to the door. It has been experimentally found that such openings are a much greater preventive against conibustion than the solid wood, since the solid wood need only char through, whereas the gases formed of combustion within the openings 20 hold the surrounding wood from charring. This is particularly true when the wood is treated with saline chemicals, which under heat produce gases in which combustion is overcome. it is obvious that such openings or grooves 20 could be made much larger in non-paneled doors; but in paneled doors only the central layer could be so grooved. The concealed tie-strip 13 would of course entirely cover the openings 20 across the upper and lower ends of the door, as the tie passes entirely around the edge of the door, as hereinbefore described.

I claim as new- 1. In a lire-door having a core, a groove in said core, a double-flanged tie-piece in said groove, and sheathing-pieces hooked over said flanges and pressed down into said groove to form the tie.

2. In a lire-door having :1 suitable core, at groove in said core, at double-flanged tie-strip nailed in said groove, and sheething-pieees having oppositely-turned edges hooked over said flanges and pressed down into said groove to form a concealed tie.

3. .ln s lire-door llzwing a suitable sheetrnetal sheathingfzt core built up of layers, and one or more of said layers provided with s series of grooves or openings, for the purpose specified.

si. in s lire-door, a core built up of a series 

